1. Field of the Invention
This invention relates to a lancing device to pierce the skin to obtain a blood sample; more particularly, a lancing device that has a shortened stroke for ejecting the lancet after lancing.
2. Background of the Related Art
Lancing devices are an unfortunate fact of life for the millions of people with diabetes who must test their blood glucose levels up to five or more times each day. They typically use the devices to draw a drop of blood from a finger, apply the blood to a disposable strip, and measure the blood glucose concentration in a meter. Obvious goals of such lancing devices are to provide an adequate sample of blood with minimal pain, inconvenience, and cost to the user.
U.S. Pat. No. 4,503,856, issued on Mar. 12, 1985 to Cornell et al., discloses a lancet device that has a tubular housing, a slidable lancet holder in the housing and a compressible spring that provides the force to move the holder linearly to a skin piercing position, after which it goes back to a neutral position.
U.S. Pat. No. 4,527,561, issued on Jul. 9, 1985 to Burns, discloses a lancet assembly that includes a second spring for retracting the lancet holder after the lancet has penetrated the user's skin (see also U.S. Pat. Nos. 4,535,769 and 4,553,541).
U.S. Pat. No. 4,895,147, issued on Jan. 23, 1990 to Bodicky et al., discloses a lancet device that includes a penetration depth selector and a mechanism for creating a vacuum after the skin has been pierced to assist in drawing blood from the puncture site.
U.S. Pat. No. 4,976,724, issued on Dec. 11, 1990 to Nieto et al., discloses a lancet device that includes a mechanism that permits the user to eject a used lancet without touching it.
U.S. Pat. No. 5,318,584, issued on Jun. 7, 1994 to Lange et al., discloses a lancet device that includes a rotary/sliding transmission system that permits a puncture to be made with less pain.